Combustion boat and shield



April 15, 1952 G. M. DREHER COMBUSTION BOAT AND SHIELD Filed April 14, 1948 y l l l u l f, f

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l l u 'l' l 1 n ll 11PM-mm INVENTOR. GEORGE M. DREHER ATTORNEYS Patented Apr. 15, 1952 George M. Dreher, Pittsburgh, Pa. Application April 14, 1948, Serial No. 20,934

My, invention relates in general to combustion apparatus for use in chemical analysis and in particular toa novel combustion boat and shield for use in such apparatus, one of the chief uses of which is its employment in the determination of` the carbon and sulfur content of iron or steel. Y

Itis customary to use a boat of suitable refractory material in combustion apparatus for Y chemicalyanalysisto contain the sample of material, e. g., iron or steel, of which it is desired to determine the carbonvand/or sulfur content.

-Such `boats are placed inside the usual refractoryIl combustion tube and` then the -tube is placed inside a heating furnace, usually an electric furnace.k The tube may be used with refractory liners between the` tube and the'` enclosed boat,V butA Iprefer touse a tube without a liner, but it is to be understood that my invention can be used where a tube liner is used. In any event the. tube or] liner soon4 .becomes unsuitable for further use due to. collections on` the `inner wall of the tube or liner of spatterings of iron slag fromthe metal samples in the combustion boat caused when the sample of iron, steel, or other f.

material is exposed to high heat say about 2500?A F., while oxygen or any other suitable gas is passed over the sample. y l

When the inside of the combustion tube or of thellner,4 becomes unduly slagged Vso that the combustion b oat cannot be properly placed in position in the/tube or liner as thecase maybe, the; affected tube or liner must be replaced, at considerable expense ify the tube. is used without a liner,- and at lesser expense if a liner is used.

To reduce the aforesaid expense, it has been `proposed to place a shield over the boat andbetween it and the combustion tube. Such Va shield can be provided much ,more cheaply than even a liner, and more readily replaced. Thus both time and expense can be saved in such chemical de# terminations'by the use of a shield over the boat.

One drawback` tothe use'of such shields, as have been heretofore used, is the tendency of the shield to become dislodged from its proper. shielding position over the boat. This isdue to the explosions which commonly occur in the tube during such determinations and to jarring of the apparatus, When a shield is dislodged from shielding position its usefulness is largelyv impairecLas some of the spatterings will adhere to the tube which is relatively expensive, and some to the shield, so that in time both` thetube and theshieldr` mus-t be replaced. Thus the. advan- 3 Claims. (o1. 263-48) tages of the known type shield are to a large degree lost.

A further drawback to the former shields which rested directly on the top of the boats was the tendency for the shields to become firmly attached to the boatv with which it was rused by the adherence of thev slag toA the top `edges of the boat and the contacting surface of theshield.l In such instances both boat and shield had to' -be discarded. My boatv and shield greatly minimizes this condition.- r

I` have observed these phenomena and have discovered how to prevent displacementV of the shield and adherence of thetube and shield in the chemical determination. I have discovered anew boat, and a shield having unique features whichv insurethat the shieldeven if moved upward from the boat, will return toa shielding position and fully protect the tube from spatterings, and one which is not prone to the adherence of the boat and shield.

.My combustion boat has features whichV are new in the art, and include special side constructions which insure that the shield will always return to shielding position if dislodged, and that the shield will not rise to a location where it will not return to a proper shielding position. I do this by shaping the side walls of the boat so as to provide a seat such as a shelf-J like projection around the outside wall of the boat 'on which the sides of the shield will rest. l also provide that the dimensions of theboat and shield are correlated with the internal di` mensions of the combustion tube so that the shield cannot be lifted so far or be dislodged to such an extent as to prevent the return oi' a dislodged shield to a spatter shielding position. This correlation also greatly minimizes the tendency ofthe boat and shield to adhere.

It is an object of my invention to provide in lcombustion analysis apparatus. a combustion boat which has side portions which guide an anti-tilting shield to a position which Iwill prevent spatteringof the inside of the combustion tube.

It is another object of my. invention to provide an anti-tilting shield having depending flanges to cover` said boat, which shield cannot tilt out .of shielding position.

It is a further object to provide a boat having seatings on the sides thereof to receive an antitilting shield having depending flanges which rest on the seatings, the proportions of the boat and shield being such as. to. be received in a combustion tube in such a manner thatgthe shield 4 nace;

cannot be dislodged to an extent that it will not reseat itself on the boat in shielding position.

Still another object of my invention is to pro- .Vide a boat and shield in which the top of the boat is normally separated from the sides of the shield, as to minimize the tendency of the boat and shield to be united by slag sputtering.

It is a still further object to provide a combustion boat and shield therefor which are simple,Y inexpensive, and which will enable relatively low cost determinations of the chemical contents of a desired material to be made by combustion analysis.

In the accompanying drawings, wherein I have shown presently preferred embodiments of myY invention:

Figure l is a schematic view showing a side elevation of a heating furnace with a combustion boat and shield in operative position in the fur- Figure 2 is an enlarged sectional view of the combustion boat and shield therefor, in position in a combustion tube, along the line II-II of Figure l;

` FgureA is a view similar to that shown in Figur-e2, but showing a modification of the boat and shield in Figure 2;

Figure is a longitudinal section of the boat and shield along the line V-V of Figure 4.V

'In therdrawings,therreference numeral I0 designatesan electric combustion furnace of known can never assume a position when conned in a tube such that the flanges of the shield can contact the top of the walls I8 and I9. However, I also contemplate a structure where the flanges and the tops of the upstanding sides of the walls may touch, or nearly so, but the proportions and shape oi the structure always assure the return of the flanges to a seating position on the steps 23 and 2li. It will also be observed thatsince the arch portion 2l is spaced above the tops of the sides I8 and I9, there will be passages between the shield I6 and the boat so as to allow free acconstructon having a combustion chamber II surrounded Yby insulated refractory walls I2. A

fand/or sulfur content of a sample of iron or steel which may be burned in the boat I5.

O In Figures 2 and 3 there is illustrated one form of combustion boat I5 and accompanying shield I6 having anti-tilting flanges. The boat which ifs o f elongated rectangular shape consists of 'a 'ibase portion I1 having upstanding sides i8 and I9 andfend portions 20 and 2|. The sides and ends enclose a well 22. The sidesY I8 and I9 are eachshaped as to provide steps or seats 23 and 24." A'handle v25 extends from oneV end of the boat.

The anti-tiltingA shield I6, which is somewhat longer than the well enclosing sides and ends includes sideilanges 26 connected by an arch portion 21. Thelshield so proportioned that when imposition with the iiiange ends on the seats 23 and 24, the sides of the flanges are spaced from thehtopoftheupstanding sides of the boat and the arch portion is spaced from the wall of tube I3, ,'Ijhe dimensions of the shield and boat are so related to the internal diameter of the tube that theshield I6 when dislodged by an explosion cannot rise` to such an extent that the materials spattered by an explosion can pass directly beyond ,theflanges of the shield. VAfterthe effects of an explosion aredissipated theshieldwill return to a-Shielding position with the flange edges resting on the seats 23 and 24. Preferably the flanges cess of gases to the contents of the boats.

In Figures 4 and 5 I have shown a modification of my device, in which a boat 30 slightly different in cross section from that shown in Figures 2 and '3 is employed. The boat includes a base 3l, upstanding sides 32 and 33, which slope downwardly and outwardly, and end portions 34 i and 35,. The sides and ends enclose a well 36.

'I he shield which is similar to that used in the structure shown in Figures 2 and 3 bears corresponding numerals with a prime aiiixed to show the corresponding parts. The sloping sides 32 and 33 provide seats for the lower ends of flanges 2B of the shield I6', and the walls of the boat are so proportionedrelative to each other and to the enclosing combustion tube with which the structure is designed to be used, that the shield must always return to a seating position on the side walls after a dislodgement. Nor can the shield be displaced to such extent that the spatterings may have a direct path to the tube, and preferably the flanges 26' may not contact the top portions o`f the walls-32 and 33.

' While Ihave described certain presently preferred embodiments of my invention itis to be understood that changes may be made therein within the scope of the following claims.

I'claim: I

l.`For `use lin a combustion analysis apparasaidlsides, said shield having depending anges andextending from a seat on one side to a seat Yon theother side and having a portion which extends overwand is spaced from the topof the sides Vf the boat, the boat and rshield being so shaped as to be received in the'tube and so proportioned that the flanges of the shield will not touch the top of the boat sides, nor will the bottom off theflanges extend above the top of the sides ofthe boat when the shield is in any operative positionrelative to the boat.

`2,. l50r use in a combustion analysis apparatus including a combustion tube, a combustion boat and a shield over the boat which boat and shield are received in said tube, said boat having upstanding sides and ends enclosing a well, a seat along said sides, said shield havingdepending flanges and extending from a seat on one side to a seat on theother side and having a portion which extends over and is spaced from the top of thesides Aof the'boat, theiboat and shield being so shaped as to be receivedin the tube and `so proportioned that the anges of the shield-will not touch the top of the boat sides, no1,l will the bottom of the lflanges extend over the top of the sides of the boat when the shield is in any operative position relative to the boat, the said shield being of s uiiicient length to extend beyond each of the Well enclosing ends.

3. For use in a combustion analysis appara- 5 tus including a combustion tube, a combustion boat'l and a shield over the boat which boat and shield are received in said tube, said boat having upstanding sides, enclosing a Well, said shield having spaced parallel depending flanges along its edges provided with supporting surfaces, said upstanding sides having supporting surfaces for engagement with said ange supporting surfaces to support said shield on said boat in a position forming a cover thereover and with said flanges projecting below the upper edges of said upstanding sides, said tube and said shield respectively having an inner surface and an outer surface, the latter surface being movable into contact with the former surface for preventing movement of the shield to a position in which one of said anges is positioned above the upper edge of one of said upstanding flanges while said lboat and shield are in said tube.

GEORGE M. DREI-IER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

